Arduino DC Motor Control

Hi, First post here.

I am looking for a simple way to control a dc motor with an arduino. I am creating a circut that takes servo input from an RC car remote and controls a motor with it. I have gotten the arduino to recive the signal from the controller but the circut I tried to power the motor with wasn't powerful enough. I realize that I could go to the RC store and by a RC speed controller but those are expensive and this is for a low budget school project.

If any one has a way to accomplish what I am trying to do with relative simplicity that would be great.


Use an NPN transistor to control larger current thru the motor. Power supply to motor +, motor- to collecter, emitter to ground. Arduino pin to 180 ohm resistor to base of transistor. High from arduino will turn allow current flow thru the transistor. Use a PWM pin to make the motor go faster or slower.

Put diode across the motor as well; cathode the motor-, anode to motor+. This will dissipate motor generated voltage when transistor is turned off.

I believe the Learning section covers this, as well as the playground.


The suggestion from Crossroads is great for small motors, but if you want to drive an RC sized motor you will need an RC Battery for power and an electronic speed controller from the hobby shop. The good news is that RC Battery technology and speed controller technology has changed a lot in the past few years so you can get good kit at a very low cost on internet auction sites.

Look for Tamiya TEU101 or TEU104, these speed controllers are supplied with Tamiya radio controlled car kits and are almost always changed to something more powerful. Anyone who has been in RC for any length of time has a draw full or these and will let one go for a few dollars. They can be used with Johnson 540 motors which are again supplied with most Tamiya models and then changed for something more powerful, these motors should be a dollar or two used.

For batteries, everyone is now using LIPO batteries, so there are thousands of unused but perfectly good Nimh and Nicad batteries allover the web.

If you can find an RC Racing club there will be someone who can give or sell you all you need, battery, ESC, 540 Motor.

So depending on the power you need go with Crossroads suggestion or look out for the parts suggested above.

Duane B.

Thanks for the suggestions.

As for using the RC Speed Controller, buying two of them would take up allmost the whole budget for the prject and there for is not possible. The method with the transister will not provide enough power so I can not use it. I have heard of using an H-Bridge? There is a kit on robot shop that is all inclusive, it uses an H-bridge, is there a way I can buy the neccesary parts that controls the motor seperatly?

Any ideas? Could i use a TIP120 transistor in order to control larger motors?

I'd go for a FET instead (make sure it's a logic level one), but be aware that without either a DPDT relay or an H bridge, you'll only be able to drive it in one direction.

So a TIP120 transistor wont work? Could you provide some more information about using a FET? if I used a fet it would control the speed and the relay / H-bridge would control direction?

So a TIP120 transistor wont work?

I didn’t say that, just that I’d use a FET instead.